Compare 2 different xml versions and highlite the differences

Question

Hi,
Currently we have xml and that is displayed on the web page using the css style sheets.
The xml we have remain the same most part but with small changes (say different version created after a week).
We want to be able to track the differences from the previous version and highlight them, the differences, when showing it in the web page.
Please advise if this can be done and how.
Thanks.

Answer 1

try
SQL> set serveroutput on
SQL> set long 50000
SQL>
SQL> declare
  2 
  3    --main
  4    xml1 xmltype := xmltype('<ROWSET>
  5                                <ROW>
  6                                  <EMPNO>7934</EMPNO>
  7                                  <ENAME>MILLER</ENAME>
  8                                  <JOB>CLERK</JOB>
  9                                  <MGR>7782</MGR>
10                                  <HIREDATE>1982-01-23T00:00:00</HIREDATE>
11                                  <REMOVED>abc</REMOVED>
12                                  <SAL>1300</SAL>
13                                  <COMM/>
14                                  <DEPTNO>10</DEPTNO>
15                                </ROW>
16                              </ROWSET>');
17    --new
18    xml2 xmltype := xmltype('<ROWSET>
19                                <ROW>
20                                  <EMPNO>7934</EMPNO>
21                                  <ENAME>MILLER</ENAME>
22                                  <JOB>CLERK</JOB>
23                                  <MGR>7782</MGR>
24                                  <ADDED>xyz</ADDED>
25                                  <HIREDATE>1982-01-23T00:00:00</HIREDATE>
26                                  <SAL>1300</SAL>
27                                  <COMM/>
28                                  <DEPTNO>10</DEPTNO>
29                                </ROW>
30                              </ROWSET>');
31    diff xmltype;
32 
33    xtype varchar2(80);
34    xpath varchar2(80);
35    xpathChild varchar2(80);
36    xnodeChild varchar2(80);
37    new_value xmltype;
38 
39    new_xml xmltype;
40 
41 
42  begin
43 
44    -- get diff
45    select xmldiff(xml1, xml2) into diff from dual;
46    dbms_output.put_line(diff.getclobval());
47 
48    -- that have
49    select x.xtype, x.xpath, x.new_value
50      into xtype, xpath, new_value
51      from xmltable(
52             xmlnamespaces('http://xmlns.oracle.com/xdb/xdiff.xsd' as "xd"
53                          ,'http://www.w3.org/2001/XMLSchema-instance' as "xsi"
54                          )
55           , '/xd:xdiff'
56             passing diff
57             columns xtype     varchar2(80) path 'local-name(xd:insert-node-before)'
58                   , xpath     varchar2(80) path'xd:insert-node-before/@xd:xpath'
59                   , new_value xmltype path 'xd:insert-node-before/xd:content/*'
60           ) x;
61 
62     dbms_output.put_line('type of doing: ' || xtype);
63     dbms_output.put_line('path for doing: ' || xpath);
64     dbms_output.put_line('value for doing: ' || new_value.getclobval());
65 
66     if (xtype = 'insert-node-before') then
67       xpathChild := substr(xpath, 1, instr(xpath, '/',-1)-1);
68       xnodeChild := substr(xpath, instr(xpath, '/',-1)+1);
69 
70       select insertChildXMLbefore (xml1,
71                                    xpathChild,
72                                    xnodeChild,
73                                    XMLType('<HIGHLIGHT>' || new_value || '</HIGHLIGHT>'))
74       into new_xml
75       from dual;
76     end if;
77 
78 
79     dbms_output.put_line(new_xml.getclobval());
80 
81  end;
82  /
<xd:xdiff xsi:schemaLocation="http://xmlns.oracle.com/xdb/xdiff.xsd http://xmlns.oracle.com/xdb/xdiff.xsd" xmlns:xd="http://xmlns.oracle.com/xdb/xdiff.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"><?oracle-xmldiff operations-in-docorder="true" output-model="snapshot" diff-algorithm="global"?><xd:insert-node-before xd:node-type="element" xd:xpath="/ROWSET[1]/ROW[1]/HIREDATE[1]"><xd:content><ADDED>xyz</ADDED></xd:content></xd:insert-node-before><xd:delete-node xd:node-type="element" xd:xpath="/ROWSET[1]/ROW[1]/REMOVED[1]"/></xd:xdiff>
type of doing: insert-node-before
path for doing: /ROWSET[1]/ROW[1]/HIREDATE[1]
value for doing: <ADDED>xyz</ADDED>
<ROWSET><ROW><EMPNO>7934</EMPNO><ENAME>MILLER</ENAME><JOB>CLERK</JOB><MGR>7782</MGR><HIGHLIGHT><ADDED>xyz</ADDED></HIGHLIGHT><HIREDATE>1982-01-23T00:00:00</HIREDATE><REMOVED>abc</REMOVED><SAL>1300</SAL><COMM/><DEPTNO>10</DEPTNO></ROW></ROWSET>
PL/SQL procedure successfully completed
SQL>
SQL> select * from v$version where rownum=1;
BANNER
Oracle Database 11g Enterprise Edition Release 11.1.0.7.0 - 64bit Production
SQL>